The present invention is directed to control devices for bicycle antitheft devices and, more particularly, to a magnetically operated bicycle antitheft device that does not require a battery in the key.
Bicycles, particularly recreational bicycles referred to as city cruisers, are inexpensive and are easy to ride, so they are widely used to commute to work or to school. Such recreational bicycles are sometimes stolen from bike stands or the like in front of train stations. To prevent this type of theft, bicycle locks such as box-shaped locks and horseshoe-shaped locks are attached to the front or back fork to lock the wheel. However, the simple structure of bicycle locks makes them easy to unlock or break and remove.
Antitheft devices which mount to the bicycle wheel hub and which make the bicycle difficult to ride also have been developed recently. The lock mechanism of such antitheft devices usually is disposed inside an internal shifting hub. When the lock mechanism is activated, the rear wheel of the bicycle is difficult to move, and noise is emitted when forcible movement is attempted. The lock mechanism can be operated between a locked state and an unlocked state with the aid of a shift control element provided to a handlebar.
More elaborate bicycle antitheft devices use electronic circuits to control a lock. For example, JP 8-260784 shows an antitheft device that may be operated either manually using a key or electronically using a transmitter. Antitheft control devices that operate electronically are often also used in automobiles and are very convenient because the user can operate the antitheft control device by merely pressing a button on a key or key holder to transmit a lock or unlock command signal to the antitheft control device. The antitheft control device then locks or unlocks the antitheft device (e.g., the locks on the automobile door) in response to the command signal
In order to receive the lock or unlock command signal at any time, the command signal receiver in conventional antitheft control devices must be powered at all times. This does not pose a problem with automobiles because automobiles use rather large batteries that are regularly recharged during operation of the automobile. However, such batteries are not used on bicycles because of the size and weight of the batteries. Electronic devices used with bicycles, such as bicycle computers and automatic transmission devices, must use small batteries that are as lightweight as possible. Such batteries are usually not rechargeable. Thus, a conventional antitheft control device would not be practical because a constantly powered signal receiver would quickly discharge the battery.
The applicant recently has developed a remote-controlled bicycle antitheft device wherein the command signal receiver is powered by a magnetically controlled switch which is closed for supplying power to the command signal receiver only when a magnetic key is placed in close proximity to the magnetic switch. The key also includes a battery-operated command signal transmitter which transmits a locking or unlocking command to the command signal receiver whenever a button on the key is pressed. While such a system solves the problems noted above, it would be even better if the key did not require its own battery.